Structural and functional characterization of HQL-79, an orally selective inhibitor of human hematopoietic prostaglandin D synthase
Structural and functional characterization of HQL-79, an orally selective inhibitor of human hematopoietic prostaglandin D synthase
复制标题
DOI：
10.1074/jbc.m506431200
复制
发表时间：
2006-06-02
影响因子：
4.8
通讯作者：
Urade, Yoshihiro
中科院分区：
文献类型：
--
作者：
Aritake, Kosuke;Kado, Yuji;Urade, Yoshihiro
我们测定了人造血前列腺素(PG)D合成酶(H-PGDS)的晶体结构，它是具有体内抗炎活性的谷胱甘肽(GSH)、镁离子和抑制剂HQL-79的四元络合物，分辨率为1.45埃。在四元络合物中，发现HQL-79位于Trp(104)和GSH之间的催化裂隙中。HQL-79的稳定性是通过它的二苯基的苯环与Trp104以及它的哌啶基团与GSH和Arg(14)通过水分子相互作用来实现的，水分子形成了一个氢键和盐桥连接到Mg2+的网络。HQL-79对底物PGH(2)竞争性抑制人H-PGDS，对GSH非竞争性抑制，K-I分别为5和3 mU(M)。表面等离子体共振分析表明，HQL-79与H-PGDS的亲和力在GSH和Mg2+存在时比不存在时高12倍(K-d，0.8mU(M))。突变研究表明，Arg14对于镁离子介导的H-PGDS与HQL-79结合亲和力的增加是重要的，而Trp(104)、Lys(112)和Lys(198)对于维持HQL结合口袋是重要的。HQL-79选择性地抑制表达H-PGDS的人巨核细胞和大鼠肥大细胞瘤细胞产生前列腺素D(2)，其IC50值约为100 mU(M)，但对其他前列腺素类化合物的产生只有轻微的影响，提示H-PGDS与环氧合酶之间存在紧密的功能联系。口服HQL-79(30 mg/kg体重)抑制抗原诱导的PGD(2)的产生，而不影响PGE(2)和PGF(2α)的产生，并改善野生型和人H-PGDS过表达小鼠的气道炎症。了解四元络合物的这种结构有助于理解HQL-79的抑制机制，并将加速基于结构的新型抗炎药物的开发，这些药物特异性地抑制PGD2的产生。
We determined the crystal structure of human hematopoietic prostaglandin (PG) D synthase (H-PGDS) as the quaternary complex with glutathione (GSH), Mg2+, and an inhibitor, HQL-79, having anti-inflammatory activities in vivo, at a 1.45-angstrom resolution. In the quaternary complex, HQL-79 was found to reside within the catalytic cleft between Trp(104) and GSH. HQL-79 was stabilized by interaction of a phenyl ring of its diphenyl group with Trp104 and by its piperidine group with GSH and Arg(14) through water molecules, which form a network with hydrogen bonding and salt bridges linked to Mg2+. HQL-79 inhibited human H-PGDS competitively against the substrate PGH(2) and non-competitively against GSH with K-i of 5 and 3 mu(M), respectively. Surface plasmon resonance analysis revealed that HQL-79 bound to H-PGDS with an affinity that was 12-fold higher in the presence of GSH and Mg2+ (K-d, 0.8 mu(M)) than in their absence. Mutational studies revealed that Arg14 was important for the Mg2+-mediated increase in the binding affinity of H-PGDS for HQL-79, and that Trp(104), Lys(112), and Lys(198) were important for maintaining the HQL-binding pocket. HQL-79 selectively inhibited PGD(2) production by H-PGDS-expressing human megakaryocytes and rat mastocytoma cells with an IC50 value of about 100 mu(M) but only marginally affected the production of other prostanoids, suggesting the tight functional engagement between H-PGDS and cyclooxygenase. Orally administered HQL-79 (30 mg/kg body weight) inhibited antigen-induced production of PGD(2), without affecting the production of PGE(2) and PGF(2 alpha), and ameliorated airway inflammation in wild-type and human H-PGDS-overexpressing mice. Knowledge about this structure of quaternary complex is useful for understanding the inhibitory mechanism of HQL-79 and should accelerate the structure-based development of novel anti-inflammatory drugs that inhibit PGD2 production specifically.